Method and apparatus for forming metal closures



2 Sheets-Sheet. 1

Sept. 24. 1940. J. J. WILLIAMS 1- M,

IETHOD AND APPARATUS FOR FORMING METAL CLOSURES Filed Nov. 1, 193? ill I ll 1 i iili .w m a a l l I 1 I I n mN Mb n r w wlwlfl ha mw 5. 40, J. J. WILLIAMS ET AL 2,215,845

IETHOD AND APPARATUS FOR FORMING METAL CLOSURES Filed Nov. 1, 1937 2 Sheets-Shoot 2 l I I II'II @7220 J. dse ahjaumani M/JM Patented Sept. 24, 1940 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR FORMING CLOSURES Virginia Application November 1, 1937, Serial No. 172,254

' 10 Claims.

The invention relates to a method and apparatus for forming metallic screw closures for containers, of the type in which the screw threads of the closures are concealed from ex- 5 terior view; the general type of closure being 11-.

lustrated in the patent to Kempien No. 725,970, April 21, 1903.

One of the objects of the invention is'to provide a new method and apparatus by which concealed thread metallic screw caps can be efilciently and inexpensively manufactured.

Another object of the invention is to provide a method and apparatus formanufacturing caps of this type, in which the blank holder is stationary, thereby avoiding the marring or disfiguring of the cap coating which often occurs during the insertion of blanks in spinning blank holders. O A further object of the invention is to provide a method and apparatus in which the forming tool is given a bodily revolving motion, in connection with a stationary cap blank, and at the same time the tool is advanced, whereby the threads are iormed by a pressing and chasing action, as distinguished from a rolling or spinhing action.

Various other objects and advantages of the invention will be apparent to those skilled in the 30 art, from the following detailed description,

when taken in connection with the accompanying drawings; in which,

Figure 1 is a vertical longitudinal sectional ,view of the preferred apparatus; parts being shown in elevation, and parts being broken away.

Figure 2 is a plan view of the apparatus.

Figure 3 is a diagrammatic view illustrating the position of certain parts, before the forming tool is moved laterally into engagement with the ,50 Referring to the drawings in more detail, nu-

meral l indicates a blank or shell holder. The blanks or shells introduced into the holder are preferably in substantially the form shown in Figure 6,where the blank 2 is provided with an 55 incurled head 3. I'hls incurled bead may be formed by engaging the edge of the blank skirt with a die having an annular curling groove, or other means may be employed for forming the incurled bead. The bead is shown as substantially circular in crosssection, though it may be of greater depth than its thickness, or of other form.

The shell holder I is stationary, and is suitably mounted in a frame 1. It has previously been the practice in the manufacture of any kind of metal screw cap, to have the cap shell rotate, but in accordance with the present invention the shell holder and the shell remain stationary, as will be described in more detail hereinafter.

The cap shells or blanks may be periodically delivered to the shell holder, by any desired means. In the present form there is shown a feed wheel 5 provided with a series of pockets 6. Plates (not shown), or other suitable means, are provided for holding the blanks in the pockets. This feed wheel is rotated step-bystep by 9. Geneva wheel 1. For operating the Geneva movement a gear 8 keyed to the main drive shaft 9, meshes with a gear ill. The ratio of these 25 gears is such that the feed wheel will move one step for each complete rotation of the main drive shaft. This brings a pocket i into alignment with the shell holder 1. The feed wheel now remains stationary and a plunger II is operated 30 to deliver the shell from the pocket to the holder. The plunger H has a shank provided with an outwardly projecting portion l2, and a spring I3 normally holds theplunger in its retracted position. m

Numeral M refers to a lever, the upper am it of which is provided with an adjustable lug it, for engagement with the projecting portion iii of the plunger II, The lower arm ll of the lever carries a roller H3 which rides in the groove ill of a cam 25 keyed to the main drive shaft 9. Thus the rotation of the drive shaft causes the plunger, at the proper instant, to move to the left (Fig. 1) and deliver a cap shell from a pocket 6 of the feed wheel to the shell holder 1. The forward movement of the shell in the holder is limited by a shoulder i. The plunger remains in its advanced position until the cap is completed, and the cam then permits the spring 53 to return the plunger to its normal or inactive position. This 5 forward and backward movement of the plunger occurs once for each cycle of operation of the machine, i. e., oncc for each rotation of the main drive shaft. The main drive shaft is continuously rotated by any desired means, as by 55 I sprocket wheel 2! driven by a sprocket chain 22,

leading from any desired source of power. After the cap has been completed it will be returned to the pocket of the feed wheel, by a knock-out pad to be hereinafter described; and the wheel is then rotated one step to carry off the completed cap and to bring another shell into position for delivery to the shell holder I.

The mechanism for operating the forming tool will now be described. Numeral 23 refers to an outer-cylindrical spindle which is eccentrically bored, and numeral 24 refers to an inner cylindrical spindle which is also eccentrically bored.

The outer spindle is appropriately mounted for rotation in standards 25 extending upwardly from a carriage 52, to be described hereinafter. Keyed to the outer spindle is a gear 26 which meshes with a gear 21 keyed to a shaft 21'. The opposite end of the shaft carries a gear 28 which meshes with gear 28' keyed to a shaft 9'. The gear 28' meshes with a gear 28" keyed to the continuously rotating main drive shaft 9. There is a 1 to 1 ratio between gears 28 and 28, so that the shaft 9' makes one revolution for each revolution of the main drive shaft 9. The gear ratio between the drive shaft and the spindle may be as desired. In the embodiment illustrated the ratio between gears 28, 28, 21 and 26 is about 3 to 1, so that the spindle makes about three revolutions for one revolution of the drive shaft, though no attempt has been made to show any particular gear ratio in the drawings.

The inner spindle 24 continuously rotates with the outer spindle 23, by reason of a pin 29 which is attached to the inner spindle and projects through a suitable opening in the outer spindle and into a slot provided in a collar slidably keyed to the outer spindle, as will appear more fully hereinafter.

As mentioned hereinbefore, both the outer spindle and the inner spindle are eccentrically bored, and mounted within the eccentric bore of the inner spindle is the shank 30 of a thread forming tool 3|. It is to be particularly noted that the threading tool does not rotate about its own axis, and to prevent such rotation a pin 32, mounted in the shank of the forming tool, passes through an opening 33 in the frame of the shell holder. The opening is shaped to permit the hereinafter described bodily revolving movement of the forming tool 3| and also to permit the hereinafter described longitudinal movement of the forming tool.

The thread forming tool is not provided with a helical bead but with two annular beads 3| arranged in spaced parallel relation. To form a screw thread in the incurled bead 3 of the cap blank 2, in accordance with the present invention, the forming tool is given what might be termed a pressing-chasing action. That is, the tool is given a bodily revolving movement which gives a pressing action, and during this bodily revolving movement the tool is moved longitudinally, which gives a chasing action.

The arrangement is such that when the axis of the threading tool is central of the blank holder, such axis coincides with the center of the outside diameter of the outer spindle, as illustrated diagrammatically in Figure 3. When the parts are in such positions, it will be noted, particularly by reference to Figure 5, that the thread forming tool is only slightly spaced from the incurled bead 2 of the cap blank; and of course this slight spacing is uniform throughout the entire circumference. And it will also be apparent, with the parts in the positions described, that the continuous rotation of the inner and outer spindles will impart no movement whatever to the forming tool, for the inner and outer spindles are in a neutral position.

To start forming the thread in the cap blank, the forming tool must be moved laterally to bring the tool into engagement with the incurled bead on the cap blank; and when the cap is completed the tool must be moved back laterally to free the cap. Any desired means may be employed for periodically effecting this lateral movement of the tool. In the particular embodiment illustrated, a collar 34 is slidably keyed to the outer spindle so that it may be moved axially of the spindle, but cannot rotate relative thereto. The pin 29, which is carried by the inner spindle, extends into a slot 35 provided in the collar. Thus the two spindles'and collar will rotate in unison. By reference to Figure 2 it will be noted that the slot is diagonal of the collar, so that as the collar is moved backward or forward, the inner spindle will be rotated relative to the outer spindle. The outer spindle is provided with a slot 23' in which the pin 29 rides, which slot permits the relative rotation between the two spindles.

For moving the collar back and forth periodically, a lever 36 is provided adjacent the collar. The lower arm 37 of the lever carries a roller which rides in a groove 38 of a cam 39 keyed to the shaft 9'. The upper arm 40 of the lever is forked, and the prongs are connected with a ring 4| associated with the collar 34.

For each complete rotation of the drive shaft, the collar will be moved in one direction to rotate the inner spindle in one direction relative to the outer spindle, to bring the forming tool into operative engagement with the incurled bead of the cap blank, and after the cap is completed the collar will be moved in the opposite direction to rotate the inner spindle back to its original position relative to the outer spindle, to free'the tool from the completed cap. The distance that the forming tool is thrown of! center determines the pressure the tool will exert on the incurled bead, and of course any desired means may be employed for varying the extent the tool is thrown off center.

When the tool is thrown off center into engagement with the incurled bead, by the relative rotation of the two spindles, the tool then travels around the interior of the blank, but withe any rotation of the tool about its own axis. The result is that the tool gives a pressing action as distinguished from a rolling or spinning action, as will appear more fully hereinafter. Figure 4 illustrates diagrammatically the relation of the inner and outer spindles, the blank holder, and the forming tool, when the tool is in operative position.

After the cap has been completed, and the tool is moved to its inoperative or neutral position, the cap is moved from the holder I into the pocket 6 from which the blank was originally delivered to the holder, by a knock-out pad 42. This pad is provided with a shank which extends through the inner spindle, and has an outwardly extending projection 43.

For operating the knock-out pad at the desired instant a lever 44 is provided. The lower arm 45 of this lever carries a roller which rides in a groove 46 of a cam 41 keyed to the shaft 9'; and the upper arm 48 carries an adjustable lug 49 positioned to engage the outwardly projecting portion .43 of the pad shank. Thus every time the main drive shaft makes a complete rotation,

the knock-out pad is moved to the right (Fig. 1) to eject a completed cap; such cap being 11- lustrated in Figure '7, and referred to by numeral A spring 50 returns the padto its normal and of course it is these combined movements of the tool which produce the desired spiral thread in the incurled bead of the cap blank. The apparatus for moving the tool longitudinally, will now be described. I I

Numeral 52 refers to a "carriage slidably mounted on ways 53. 'The threading tool and all of its operating parts, are mounted on this carriage, and the gear 28" on the main drive shaft 9 has a somewhat wider face than gear 28' with which it meshes, so that the continuous rotation of the various gears on the carriage is not interrupted when the carriage is moved back and forth.

For moving the carriage back and forth at the desired time and speed, acam- 54 is keyed to the main drive shaft 9. An arm 55, projecting from the carriage, is provided with 'a roller 56 which rides in the groove 51 of the cam 54.

In the particular embodimentdllustrated, the carriage and forming tool" are moved from the right to theleft (Fig. l): while the thread is being formed in the cap. If the thread to be formed in thecap is in the proportion of 5 ei'ghtthreads'to th'e inch, the tool"wi ll be moVedt Atheleft- A; of an inch for each comple'te bodilymovement of revolution of'the'forming tooL- '01- course the pitch can be changed as desired,and;obviously the forming tool can 'b mov'edfrom the leftto the right, informing the threadiinstead' of from the right to the left.

The operation-will 'now'be described. The blanks with the incurled-bead. are carried. stepby-step into alignment with the. blank holder I by the feed wheel 5, and at the proper instant the plunger l-l isoperated to push a blank from a pocket 6 into the blank holder.- The;blank holder and 1 blankremain stationary.

When the blank is "delivered to the holder, the axis of the'threading tool is central of the blank holder, and coincides with the center of the outer diameter of the outer spindle 23. That is, the parts are in the positions shown in Figures 3 and 5. -When-, in this position, the threading tool is preferably spaced only slightly from the incurledbead on the cap blank.

to th''llongjitudinal position of the tool when the operation commences, it will be noted by reference to Figure 1 that the beads on the forming tool are within the cap blank, and hence in this specific embodiment the tool will be moved to the left, or away from the cap blank, as the thread forming operation progresses. Of course the operation could be modified so that the tool would move-from the right to left, during the thread forming operation, if desired.

As stated above the cap blank does not rotate, and the threading tool does not rotate, but the latter has a bodily revolving movement combined it with a longitudinal movement.

The inner and outer spindles, which are in effect a single spindle with relatively movable parts, are rotating continuously, but no movement is imparted to the threading tool, for the inner and outer spindles are in neutral position. The blank having been delivered to the holder, the cam 39 now throws the lever 36 and thereby moves the collar 34 longitudinally of the spindles. Upon such movement of the collar, the diagonal slot 35 therein, and the cooperating pin 29, cause the inner spindle to be rotated relatively to the outer spindle; the outer spindle being provided with a slot 23' to permit the relative rotation.

This relative rotation of the spindles throws the thread forming tool oil? center, and into operative engagement with the incurled bead oi the cap blank. The extent the tool is moved off center determines the pressure exerted on the incurled bead, and of course the extent it is moved of! center can be varied by any desired means.

When the tool is moved off center, one of the annular beads on the thread forming tool is brought into engagement with the incurled bead, and a portion of a thread is formed at the point where the annular bead of the tool is forced into the. inclurled bead of the cap. And it is to be noted that as neither the blank nor the tool is rotating, the thread portion at that point is formed by substantially a pressing action.

, Let itbe assumed, merely for the purpose of explanation, that a north point of the thread forming tool coincides with a north point of the cap blank, when they are originally brought into thread-forming relation, and a thread portion is thereby pressed at the north point. The outer and inner spindles are of course continuously rotating, and the pin 32 prevents any rotation of the threading tool. But the threading tool has been moved oil-center, and hence it will have a bodily revolving movement around the incurled head, in thread-forming relation therewith. During this bodily movement, the abovementioned north point of the threading tool remains substantially aligned with the north point of" the cap blank, so it will be apparent that the whole-'eilect of this bodily movement of revolution' is substantially a pressing operation, rather than a rolling or spinning operation.

The bodily movement of revolution of the tool does not, of course produce a thread. In order that athread may be formed the tool must be moved longitudinally across the cap bead, simultaneously with the movement of revolution.

Hence at the time the tool is moved off-center to engage the incurled bead of the blank, the cam 54 causes the carriage 52 and the threading 'tool carried thereby, to move to the left (Fig. 1). The movement'of the carriage and tool will be governed by the desired pitch of the thread to be formed. For'example, if the thread is to be in the proportion of eight threads to the inch, the tool will be moved to the left inch for each complete bodily movement of revolution of the forming tool.

It is thus apparent that the thread is formed upon the cap. 'I'he- 54 now reverses the movement of the carriage 52, causing it to travel to the-right-,. to its original position. v

As the carriage and tool are moved to the right the knock-out pad- 42 .is operated by the-cam 4,1,;

to push thehcompleted cap :backinto the pocket 6 from which it i was originally delivered. ejecting acompleted cap, the earns 20 and 41 are preferably so timed that the cap is held between the knock-out pad" and plunger ll, until it isplaced in the pocket 6. k a v The cam 41 nowallows the spring 50 to return the knockout padi to ;its inactive position: the wheel is moved one station to carry off the compl'etedcap-and to bring =;a new blank into position tobe delivered tothe holder. The cycle isthenrepeated;

Havingfully described the invention, what we claim is:? 5

1. The method of forming concealedithread.

pressingeoutwardlylportions of the metal, of- ,the

uncurled; bead by, causing. a substantially, on rotatingthreadeforming :t001 to; ;move bodily about ti e interiorv of :the; blank in piessing em gagement with the. incurled bead and simultaneously moving. the tool transversely of vthe bead. .1111. ii t;

3. The method of forming concealed thread single-shell metallic closures, which comprises forming an incurled bead one blank skirt, and while the blank is maintained stationary pressing outwardlyportions of the metal of the .-un curled bead bycausing a substantially .non-rotating thread-forming tool to move bodilyaround the interior of the blank inpressing engagement with the incurled bead,'and simultaneously moving the tool transversely of the bead.

4. An apparatus for manufacturing concealed thread single-shell metallic closures, including a blank holder, a substantially non-rotating threadforming tool, means for moving the non-rotating tool bodily about the interior of a blank in the blank holder. and means for simultaneously moving the tool longitudinally.

5. An apparatus for manufacturing concealed thread single-shell metallic closures, including a blank holder, a thread-forming tool, means for substantially preventing rotation of the tool, means for imparting a bodily revolving .movement to the tool, and means for simultaneously imparting a longitudinal movement to the tool.

6. Anapparatusfor manufacturing concealed thread single-shell metallic closures, including a blank-holder, a thread-forming tool, means for substantially preventing rotation of the tool, means for moving the tool laterally into and out of engagement with a blank in the blank holder, means for imparting a bodily revolving movement to the tool, and means for simultaneously imparting a longitudinal movement to the tool.

7. An apparatus for manufacturing concealed thread single-shell metallic closures, including a blank holder having a smooth cylindrical interior, the front and rear ends of said holder being open, means for feeding a blank with an incurled bead through the rear end of the holder, a thread-forming tool adapted to extend through the front end of the holder, means for moving the tool bodily around the interior of the blank in pressing engagement with the incurled bead,

and means for simultaneously imparting a longitudinal movement to the tool.

8. An apparatus for manufacturing concealed thread single-shell metallic closures, including a blank holder having a smooth cylindrical interior, the front and rear ends of said holder being open, an inturned shoulder at the forward end of the holder, means for feeding a blank with parting a longitudinal movement to the tool.

. 9. An-apparatus for manufacturing concealed single-shell metallic closures, including a blank holder. having a smooth cylindrical interior, the front and rear ends of said holder being open. means for feeding a blank with an incurled bead through the rear end of the holder, a threadforming tool adapted to extend through the front end of the holder, means for. moving the tool bodilyw around the interior of the blank in pressing engagement with the incurled bead, means for simultaneously imparting a longitudinal movement'to'the tool, and means for discharging the completed closure through the rear end of the holder;

10. An apparatus for manufacturing concealed thread single shell metallic closures. including a non-rotating blank holder, said blank holder adapted to hold a blank having an incurled bead, a substantially non-rotating threadforming tool,means for moving one of the aforesaid elements with respect to the other of the aforesaid elements to bring said thread-forming tool into pressing engagement with the incurled bead, means for imparting a bodily revolving movement to one of the aforesaid element-s relative to the other of the aforesaid elements, and means for causing a relative longitudinal movement between the aforesaid elements.

JOHN J. WILLIAMS. JOSEPH BAUMAN. 

